伸ばす: extending meeting time and developing one's strengths
Distinguish extending a meeting by thirty minutes from practising to develop one's strongest skills. Read the added time, the object of development, and the difference between an action and a purpose.
Extending the time of a meeting
伸ばす (のばす) includes extend and develop. 「会議の時間を三十分伸ばしました。」 means “We extended the meeting by thirty minutes.” The object is the meeting's time, and thirty minutes is the amount added.
Thirty minutes is the extension, rather than the total length of the meeting. The completed extension is also different from a plan to shorten it. Reading the object and amount together makes the physical time change clear.
Practising to develop a strong area further
「得意な分野をさらに伸ばすため、毎日練習しています。」 means “I practice every day to further develop my strongest skills.” The purpose concerns further development of an area of strength. The object shifts from meeting time to an ability.
Daily practice is an ongoing activity stated in the sentence, but achievement of the development goal is not. Do not measure that skill development as an extra amount of time like thirty minutes. Keep the purpose distinct from the current practice.
Compare the object as well as the action
The verb is the same in both examples, but meeting time and an area of strength give different meanings. For time, identify the amount added; for ability, identify what is to be developed. The verb does not make every object a measure of length or duration.
Preserve the timing too. Extending the meeting is a past action, while daily practice is a current activity directed toward development. Practising does not by itself establish achieved improvement or a change in a meeting schedule.
How does 伸ばす differ between adding thirty minutes to a meeting and practising to develop a strong skill?
Show the answer and why
Thirty minutes is the amount added to the meeting, not its total duration. The other sentence states the purpose of developing an ability and the ongoing daily practice. It does not measure development as added time or report an achieved improvement.